The present invention relates to controlling the handset volume of a telephone call, and more particularly to user control of the speech volume transmitted by the central office switch by adjusting the line card transmit and receive pad values.
When using a telephone, there may be several reasons that a different handset audio volume level is desired. For example, a hearing impaired individual may require a higher volume in order to hear the conversation. The listener may be located in a noisy environment that interferes with his ability to hear the conversation. A poor connection may result in an attenuated signal. One or more off-hook extension telephones may attenuate the signal such that hearing the conversation is difficult for all of the parties. Also, the handset audio volume may need to be lowered if the received telephone signal is too strong, or the speaker is talking particularly loud.
There also may be a desire to control the mouthpiece volume on the outgoing signal of a telephone user. For example, an individual may speak at a low volume making it difficult for the listener to hear, and desire to increase the transmit volume of his handset. Also, a participant in a conference call may be in a noisy environment that is disrupting the conference call or even causing his line to inadvertently gain control of the call, and the participant desires to reduce the transmit volume of the handset.
Many telephones have volume and mute controls that let the listener control the handset audio volume. This solution requires purchasing a specially equipped phone. Another suggested solution to control the handset audio volume uses centrally located digital network transmission components, such as echo cancelers (U.S. Pat. No. 5,539,806), or digital signal processors found in encoding/decoding components (U.S. Pat. No. 6,061,431). Another suggested solution uses a separate control circuit that is added to a trunk circuit that allows a user of the trunk circuit to control the volume through DTMF tones (U.S. Pat. No. 4,017,695). This circuit requires the user to hold a DTMF key for more than one second to allow the control circuit to intercept the tone. This method interferes with other services the user may subscribe to that require the entry of keypad tones, and requires the addition of a separate control circuit for each trunk circuit.
It is an object of the present invention to provide a system that will allow a subscriber to control the audio volume of a telephone call that uses existing central office switch circuitry.
Another object of the present invention is to provide such a system such that it will not interfere with other services the subscriber may have.
The invention of Applicant is a switch based feature that allows subscribers to adjust their incoming or outgoing audio signal strength. The invention adjusts the value of the transmit pad or receive pad on the subscriber line card to adjust the strength of the audio signal transmitted to, or received from, the network. The subscriber controls the feature by first sending a switch-hook flash to the switch, entering the DTMF keypad feature code and transmit or receive volume parameter, and then returning to the call.